1. Field of the Invention
The present invention relates to a magnetoresistance effect element having a magnetic artificial lattice film and a high magnetoresistance ratio.
2. Description of the Related Art
Magnetoresistance effect elements utilizing the magnetoresistance effect have been used in a variety of applications such as a magnetic sensor and a magnetic head. A magnetoresistance effect element using a magnetic body has excellent temperature stability and a wide temperature range. A permalloy thin film exhibiting a magnetoresistance ratio of about 2% has been widely used in a conventional magnetoresistance effect element using a magnetic body. However, a sufficient high sensitivity cannot be obtained with this element because the permalloy thin film has a low magnetoresistance ratio.
To the contrary, in recent years, an artificial lattice film having a multilayered structure consisting of magnetic and nonmagnetic layers alternately stacked on each other at a period on the order of several to several tens of A such that upper and lower magnetic layers are magnetically coupled through a corresponding nonmagnetic metal layer in an anti-parallel manner has received a great deal of attention because the artificial lattice film exhibits a great magnetoresistance effect. Artificial lattice films such as (Fe/Cr).sub.n (Phys. Rev. Lett., Vol. 61, p. 2472 (1988)), and (Co/Cu).sub.n (J. Mag. Mag. Mat., Vol. 94, p. 1.1 (1991)) have been developed. These films have a magnetoresistance effect 10 times or more that of a conventional permalloy thin film. When applications to a magnetoresistance effect element or the like are taken into consideration, the magnetoresistance effect of the conventional artificial lattice film is not yet sufficient. This artificial lattice film has a saturation magnetic field as large as several kOe. For this reason, in applications to magnetoresistance effect elements, it is difficult to obtain a high sensitivity with a small change in magnetic field.